Large algae fern
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Large algae fern ( Azolla filiculoides ) |
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The large algae fern or fern- like algae fern ( Azolla filiculoides ) is a species of the algae fern genus within the swimming fern family (Salviniaceae). It is a floating leaf plant that is native to the New World and is a neophyte in some parts of Central Europe .
description
The large algae fern is an annual to deciduous, perennial herbaceous plant that is between one and ten centimeters in size and often breaks up into smaller pieces. The leaves are generally bluish green in color and turn reddish brown in autumn. The leaflets consist of two millimeter long, roof-tile-like lobes and are not wettable because of the papillae . Their sporangia (spore capsules) sit on the lower lobes of the side branches.
ecology
The large algae fern is a very small, unwettable floating leaf plant ( hydrophyte ). The cyanobacteria Anabaena azollae , which live in symbiosis in their leaf hollows , can bind atmospheric nitrogen. This symbiosis can bind up to 50 kg of nitrogen per hectare per year. To use the will Azolla in East Asia such. Sometimes used in rice fields for green manuring , because after the fern dies, the nitrogen compounds released are available to the rice plants.
The plants divide very vividly as a whole and can be spread by clinging to waterfowl. An additional spread takes place via the culture of the plant in garden ponds and via emptied aquariums outdoors, because there the species is used as an ornamental plant. When the water dries up, the species forms landforms. In the case of the large algae fern, there is heterospore ; H. there are microspores and Mega spores formed. Sexual reproduction is very complicated. At maturity, fruit-like structures develop, so-called sporocarpies . Spore ripening extends from August to October.
The number of chromosomes is 2n = 40, 44 or 66.
Occurrence
America (North America, South America to Chile and Argentina), often abducted and z. T. naturalized. The fern multiplies rapidly, covering the surface of South African waters with a thick carpet of leaves. As a result, important waterways become impassable, and irrigation pumps and pipes become clogged. The dying plant matter removes oxygen from the water, creating a putrid stench. Grazing cattle mistake the carpet for grass, get caught in it and drown.
In Germany , the large algae fern has been a neophyte on the Upper Rhine since 1870 .
The great algae fern thrives in warm, eutrophic to very eutrophic, lime and nutrient-rich waters. Only a few Lemna species ( Lemna minor , Lemna minuscula , also Spirodela polyrhiza ) can survive in optimal Azolla blankets and form the characteristics of the Lemno Spirodeletum. The great algae fern is also a species of the Lemno minoris-Azolletum filiculoidis. On the Upper Rhine , the large algae fern can sometimes be found all year round, it can withstand the first frosts well and, through its vegetative reproduction, builds up huge floating covers (up to 1 hectare in size), especially in the late year. These blankets are characterized by a red-brown color in sunny places. Even so, the species seems to be very volatile. Sporangia are very abundantly formed everywhere.
The species is already highly invasive on the Lower Rhine in North Rhine-Westphalia .
Taxonomy
According to Euro + Med, there is Lam for Azolla filiculoides . the synonym Azolla caroliniana Willd.
literature
- Schmeil-Fitschen: The flora of Germany and the neighboring countries . 95th edition, 2011, ISBN 978-3-494-01498-2
- Henning Haeupler , Thomas Muer: picture atlas of the fern and flowering plants of Germany (= the fern and flowering plants of Germany. Volume 2). 2nd, corrected and enlarged edition. Published by the Federal Agency for Nature Conservation. Ulmer, Stuttgart 2007, ISBN 978-3-8001-4990-2 .
- Oskar Sebald, Siegmund Seybold, Georg Philippi: The fern and flowering plants of Baden-Württemberg . Ulmer Verlag, Volume 1
- Ruprecht Düll , Herfried Kutzelnigg : Pocket dictionary of plants in Germany and neighboring countries. The most common Central European species in portrait. 7th, corrected and enlarged edition. Quelle & Meyer, Wiebelsheim 2011, ISBN 978-3-494-01424-1 .
- Heinz-Dieter Krausch: color atlas water and bank plants . Eugen Ulmer Verlag, 1999, ISBN 3-8001-3352-0.
- Christel Kasselmann : aquarium plants. Ulmer Verlag, Stuttgart 1995; 2nd, revised and expanded edition 1999, ISBN 3-8001-7454-5 , p. 138.
Individual evidence
- ^ Tropicos. [1]
- ^ Erich Oberdorfer : Plant-sociological excursion flora for Germany and neighboring areas . With the collaboration of Angelika Schwabe and Theo Müller. 8th, heavily revised and expanded edition. Eugen Ulmer, Stuttgart (Hohenheim) 2001, ISBN 3-8001-3131-5 , pp. 88 .
- ↑ Christenhusz, M. & Raab-Straube, E. von (2013): Lycopodiophytina. - In: Euro + Med Plantbase - the information resource for Euro-Mediterranean plant diversity. Datasheet Azolla In: Euro + Med Plantbase - the information resource for Euro-Mediterranean plant diversity.
Web links
- Large algae fern. In: FloraWeb.de.
- Large algae fern . In: BiolFlor, the database of biological-ecological characteristics of the flora of Germany.
- Profile and distribution map for Bavaria . In: Botanical Information Hub of Bavaria .
- Thomas Meyer: Algae fern data sheet with identification key and photos at Flora-de: Flora von Deutschland (old name of the website: Flowers in Swabia )